Cartridge system for a probing head for an electrical test probe

ABSTRACT

A cartridge system includes a main probing head body with electronics positioned therein. Further, the cartridge system includes a probing tip cartridge having a probing tip. A minimally inductive electrical contact mechanism electrically couples the electronics to the probing tip when the probing tip cartridge is in mating relationship with the main probing head body. The types may be, for example, a pointed tip, a socket tip, or a grabber tip. In one preferred embodiment the probing tip cartridge further includes at least one foot.

The present application is a continuation of U.S. patent applicationSer. No. 10/607,791, filed Jun. 27, 2003, now U.S. Pat. No. 6,828,769.U.S. patent application Ser. No. 10/607,791 is a continuation of U.S.patent application Ser. No. 09/629,258, filed Jul. 31, 2000, now U.S.Pat. No. 6,605,934. The present application is based on and claimspriority from these applications, the disclosures of which are herebyincorporated herein by reference.

BACKGROUND OF INVENTION

The present invention relates generally to a cartridge system for aprobing head for an electrical test probe, and specifically to a probinghead cartridge system that includes a main probing head body and aswitchable and replaceable probing tip cartridge.

An electronic test probe generally consists of a probing head, a cable,and a connector. The probing head may have an integral or replaceableprobing tip that is suitable for making an electronic contact withelectrical components. The probing head is attached to a first end ofthe cable and the connector is attached to the opposite end of thecable.

Electronic test probes are used to provide an electrical connectionbetween electrical components and testing instruments such asoscilloscopes and other measuring, monitoring, diagnostic, and signalprocessing instruments. As the size of electrical components decrease,probing tips get smaller.

One type of probing head is a complete unit with an integral,non-replaceable tip. Although this type of probing head provides for anelectrical connection with very low resistance, if the tip breaks, theentire head must be replaced. Also, an integral tip limits the user to asingle tip unless the user replaces the entire probing head.

Another type of probing head includes a head assembly with a hollowsocket that couples with a switchable and replaceable probing tip. Oneexample of this type of probing head is shown in U.S. Des. Pat. No.354,923 to Nightingale. One problem with this socket-type-probing headis that the tips often slide out of the socket. Another problem is thatthe small tips are easily lost and, once lost, hard to find. Examples ofother references that disclose probes with replaceable tips include U.S.Pat. No. 4,552,465, U.S. Pat. No. 4,849,689 to Gleason et al., JapaneseDocument JP11258270A, and Japanese Patent No. 10282140. In general,these replaceable probing tips are easily broken and, once broken, hardto remove and replace.

U.S. Pat. No. 5,334,931 to Clarke et al. (the “Clarke reference”) setsforth a probing head that may be readily replaced. It is designed with acantilevered portion that is meant to reduce contact tip breakage.However, if the contact tip does break, it is easy to remove andreplace. The Clarke reference does not disclose a solution for moderncomplicated test probes that include expensive electronics and must havelittle or no inductance.

U.S. Pat. No. 4,209,742 to Bender et al. (the “Bender reference”) isdirected to an electrical probe with a modular form of construction foran old technology modular probing head (signal sensing head), a cablewith a plug at both ends, and an output termination. One or both plugsare suitable for connecting to the probing head. If the cable is broken,it is simply disconnected at both ends and replaced. Similarly, theprobing head can be disconnected and replaced. Because the Benderreference is directed to old technology, it does not disclose a solutionfor modern complicated test probes that include expensive electronicsand must have little or no inductance or capacitance.

BRIEF SUMMARY OF THE INVENTION

Unlike the prior art, the present invention provides a solution formodern complicated test probes that include expensive electronics andmust have little or no inductance or capacitance.

The present invention relates generally to a cartridge system for aprobing head for an electrical test probe, and specifically to a probinghead cartridge system that includes a main probing head body and aswitchable and replaceable probing tip cartridge. The body may include asubstantial portion of the electronics that make probing headsexpensive. Each cartridge would include a fixed tip. However, thecartridges could be made with different types of tips such as a pointedtip, socket tip, or grabber tip. Those embodiments in which the tips arefixed in the cartridge have significantly lower capacitance than designsin which tips are exchanged within the socket.

A cartridge system of the present invention includes a main probing headbody with electronics positioned therein. Further, the cartridge systemincludes a probing tip cartridge having a probing tip. An electricalcontact mechanism electrically couples the electronics to the probingtip when the probing tip cartridge is in mating relationship with themain probing head body. The types may be, for example, a pointed tip, asocket tip, or a grabber tip.

The foregoing and other objectives, features, and advantages of theinvention will be more readily understood upon consideration of thefollowing detailed description of the invention, taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an exploded perspective view of one preferred embodiment of aprobing head cartridge system of the present invention including a mainprobing head body and a probing tip cartridge.

FIG. 2 is a cross-sectional side view of the probing head cartridgesystem showing the internal electronics and the electrical contactmechanism contacting a conductive surface when the probing tip cartridgeis in mating relationship with the main probing head body.

FIG. 3 is a cross-sectional bottom view of the probing tip cartridge.

FIG. 4 is an exploded perspective view of an alternate preferredembodiment of a probing head of the present invention.

FIG. 5 is an exploded perspective view of one preferred embodiment of anelectrical test probe with an integrated grabber cartridge of thepresent invention including a main probing head body and a probing tipgrabber cartridge.

FIG. 6 is an exploded cross-sectional side view of the electrical testprobe with an integrated grabber cartridge.

FIG. 7 is a bottom view of the integrated grabber cartridge.

FIG. 8 is an exploded perspective view of an alternate preferredembodiment of a probing head with an integrated grabber of the presentinvention.

FIG. 9 is a perspective view of an integrated grabber coupling with acircuit board device.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1–3, the present invention is directed to a cartridgesystem 20 for a probing head 22 for an electrical test probe thatincludes a main probing head body 24 and a switchable and replaceableprobing tip cartridge 26. The main probing head body 24 may include asubstantial portion of the electronics 28 that make probing headsexpensive. And the probing tip cartridge 26 would include a probing tip30 such as a pointed tip (FIG. 4), socket tip (FIGS. 1 and 2), grabbertip (not shown), or any other type of probing tip.

As shown in FIGS. 1 and 2, the main probing head body 24 has an interiorcompartment in which the electronics 28 are positioned. The main probinghead body 24 also has an external peripheral surface 25. Havingelectronics in the main probing head body 24 is important because it canbe used to amplify a portion of the signal for transmission back to thetesting instrument without altering the signal. It should be noted thatboth active and passive electronics are contemplated as “electronics”herein. Older technology did not need electronics in the probing head22.

An electrical contact mechanism 32 is electrically coupled to theelectronics 28. The electrical contact mechanism 32 may be, for example,a signal spring contact, a leaf spring, a pogo pin, or a coil spring.These exemplary electrical contact mechanisms 32 are not meant to limitthe scope of the invention. In the preferred embodiment, the electricalcontact mechanism 32 protrudes from the main probing head body 24. Thisis shown in FIGS. 1 and 2. Further, as shown in FIGS. 1 and 2, theelectrical contact mechanism 32 may protrude from the externalperipheral surface 25.

A probing tip cartridge 26 of the present invention includes a probingtip 30 with a conductive exterior surface such that at least part of theconductive surface is exposed to form an exposed conductive surface 34.FIG. 4 shows an integral probing tip. FIGS. 1–2, however, show a socketprobing tip 30 for coupling with a secondary probing tip 36. If asecondary probing tip 36 is used, it is in electrical connectivity withthe exposed conductive surface 34. The electrical contact mechanism 32contacts the conductive surface 34 when the probing tip cartridge 26 isin mating relationship with the main probing head body 24.

In an alternate embodiment (not shown) an electrical contact mechanismcould be integrated into the probing tip cartridge 26 so that itprotrudes therefrom. In this alternate embodiment (not shown), theelectrical contact mechanism would contact a conductive surface on theelectronics 28 when the probing tip cartridge 26 was in matingrelationship with the main probing head body 24.

If the probing head 22 shown in FIG. 2 were used to probe a component ona circuit board, the signal would follow the following exemplary path.First, as the secondary probing tip 36 touched the circuit boardcomponent, the signal would enter the secondary probing tip 36. Thesignal would then travel from the secondary probing tip 36 to theprimary probing tip 30. As the primary tip 30 has an exposed conductivesurface 34 the signal would travel from the exposed conductive surface34 to the electrical contact mechanism 32. The electrical contactmechanism 32 would then allow the signal to flow to the electronics 28.Finally the signal would go through the cable 38 to the testinginstrument 40.

The cartridge system as shown preferably has a main probing head body 24with a set of gripping jaws 41 a and a probing tip cartridge 26 with aset of gripping surfaces or rails 41 b. The gripping jaws 41 a grip thegripping surfaces 41 b to hold the probing tip cartridge 26 in place.The probing tip cartridge 26 may be further secured by a foot 42extending into the main probing head body 24 through an opening 44defined therein. Alternatively, as shown in FIG. 4, the probing tipcartridge 26 may be held in place by a rear boot 46 gripping both theprobing tip cartridge 26 and the main probing head body 24.

FIGS. 5–9 show various embodiments of an integrated grabber 100. FIGS.5–7 show an integrated grabber cartridge system in which the mainprobing head body 24 is substantially similar to that shown in FIGS.1–4. The cartridge, however, is an integrated grabber cartridge 120. Theactuator 126 and grabber tip 128 are exposed from the integrated grabbercartridge 120 at opposite ends so that by pushing and pulling theactuator 126 the grabber tip 128 opens and closes. It should be notedthat alternate actuating means are possible (for example, a sideactuator). FIG. 8 and FIG. 9 show an alternate embodiment of theintegrated grabber in which the grabber is integrated into a cartridgethat can be attached to a probing head body.

A method for using a cartridge system 20 of the present inventionincludes the step of protruding the electrical contact mechanism 32 fromthe main probing head body 24. Then the probing tip cartridge 26 isbrought into mating relationship with the main probing head body 24.This causes the electrical contact mechanism 32 to be coupledelectronically with the conductive surface 34. Finally, the probing tipcartridge 26 is secured in mating relationship with the main probinghead body 24.

It should be noted that the step of bringing the probing tip cartridge26 into mating relationship with the main probing head body 24 may bedone in many ways. For example, as shown in FIGS. 1 and 2 the probingtip cartridge 26 may be slid forward so that the gripping surfaces 41 bmove forward into the gripping jaws 41 a. In FIG. 4, on the other hand,the probing tip cartridge 26 slides backward into mating relationshipwith the main probing head body 24. Other types of connections could beused, for example, the probing tip cartridge 26 could be snap fit intomating relationship with the main probing head body 24. Other examplesinclude adhesive, mechanical connectors, friction fits, or trapped in aliving hinge.

It should be noted that the step of securing the probing tip cartridge26 and the main probing head body 24 in mating relationship might bedone in many different ways. For example, FIGS. 1–3 show an embodimentin which the step of securing further includes the step of extending afoot 42 of the probing tip cartridge 26 into the main probing head body24 through an opening 44. Alternatively, FIG. 4 shows an embodiment inwhich the step of securing further includes the step of gripping boththe probing tip cartridge 26 and the main probing head body 24 with arear boot 46.

The method of the present invention also contemplates switching orreplacing the probing tip cartridge 26 as needed by the user. To switchthe probing tip cartridge 26 the user first releases the probing tipcartridge 26 from its mating relationship with the main probing headbody 24. Then the user removes the probing tip cartridge 26. Next, theuser provides a replacement probing tip cartridge 26 having a probingtip 30 with a conductive surface 34 defined therein, at least part ofthe conductive surface 24 being exposed. The user then brings thereplacement probing tip cartridge 26 into mating relationship with themain probing head body 24. In doing this step the electrical contactmechanism 32 electrically couples with the conductive surface 34.Finally, the user secures the replacement probing tip cartridge 26 inmating relationship with the main probing head body 24.

It should be noted that the present invention contemplates that theprobing tip cartridge 26 may be disposable. Alternatively, the probingtip cartridge 26 may have a socket as a probing tip 30 so that brokentips could be replaced.

The terms and expressions that have been employed in the foregoingspecification are used as terms of description and not of limitation,and are not intended to exclude equivalents of the features shown anddescribed or portions of them. The scope of the invention is defined andlimited only by the claims that follow.

1. A cartridge system for an electrical test probe, said systemcomprising: (a) a main probing head body; (b) electronics positionedwithin said main probing head body; (c) a minimally inductive electricalcontact mechanism directly electrically coupled to said electronics,said electrical contact mechanism protruding from said main probing headbody; (d) a probing tip cartridge interconnectable with said mainprobing head body; (e) a probing tip with a conductive surface, at leastpart of said conductive surface being exposed; (f) said probing tipinterconnectable with said probing tip cartridge; (g) said probing tipcartridge being a switchable and replaceable probing tip cartridge; (h)said electrical contact mechanism contacting said conductive surfacewhen said probing tip cartridge is in mating relationship with said mainprobing head body; and (i) a signal testing instrument functionallyassociatable with said probing tip so that a signal through said probingtip may be measured by said signal testing instrument; (j) wherein saidcartridge system is suitable for high bandwidth applications.
 2. Thesystem of claim 1, said electronics being selectively electricallycoupled to said signal testing instrument via a cable.
 3. The system ofclaim 1, said probing tip cartridge being disposable.
 4. The system ofclaim 1, said probing tip being a socket for receiving other probingtips.
 5. The system of claim 1, said electrical contact mechanism beinga signal spring contact.
 6. The system of claim 1, said electricalcontact mechanism being a leaf spring.
 7. The system of claim 1, saidprobing tip cartridge being an integrated grabber cartridge.
 8. Thesystem of claim 1, further comprising: (a) said main probing head bodyhaving a set of gripping jaws; and (b) said probing tip cartridge havinggripping surfaces; (c) wherein said gripping jaws grip said grippingsurfaces.
 9. The system of claim 1 wherein said probing tip cartridge isheld in place by a foot extending into said main probing head body. 10.The system of claim 1 wherein said probing tip cartridge is held inplace by a rear boot gripping both said probing tip cartridge and saidmain probing head body.
 11. A method for using a cartridge system for anelectrical test probe, said method comprising the steps of: (a)providing a main probing head body having electronics positioned thereinand a minimally inductive electrical contact mechanism directlyelectrically coupled to said electronics; (b) providing a switchable andreplaceable probing tip cartridge; (c) providing a probing tip with aconductive surface defined therein, at least part of said conductivesurface being exposed, said probing tip interconnectable with saidprobing tip cartridge; (d) protruding said electrical contact mechanismfrom said main probing head body; (e) bringing said probing tipcartridge into mating relationship with said main probing head body; (f)coupling electronically said electrical contact mechanism with saidconductive surface; (g) securing said probing tip cartridge in matingrelationship with said main probing head body; (h) providing a signaltesting instrument; (i) associating functionally said probing tip withsaid signal testing instrument; and (j) testing a high bandwidth signalthrough said probing tip using said signal testing instrument.
 12. Themethod of claim 11 wherein said step of securing further comprises thestep of securing said probing tip cartridge in mating relationship withsaid main probing head body by extending a foot of said probing tipcartridge into said main probing head body.
 13. The method of claim 11said step of securing further comprises the step of securing saidprobing tip cartridge in mating relationship with said main probing headbody by gripping both said probing tip cartridge and said main probinghead body with a rear boot.
 14. The method of claim 11 furthercomprising the steps of: (a) releasing said probing tip cartridge fromits mating relationship with said main probing head body; (b) removingsaid probing tip cartridge; (c) providing a replacement probing tipcartridge having a probing tip with a conductive surface definedtherein, at least part of said conductive surface being exposed; (d)bringing said replacement probing tip cartridge into mating relationshipwith said main probing head body; (e) coupling electronically saidelectrical contact mechanism with said conductive surface; and (f)securing said replacement probing tip cartridge in mating relationshipwith said main probing head body.
 15. The method of claim 11 furthercomprising the step of gripping surfaces of said probing tip cartridgeusing a set of gripping jaws of said main probing head body.
 16. Acartridge system for an electrical test probe, said system comprising:(a) a main probing head body; (b) electronics positioned within saidmain probing head body; (c) a switchable and replaceable probing tipcartridge; (d) a probing tip interconnectable with said probing tipcartridge; and (e) a minimally inductive electrical contact mechanismfor electrically coupling said electronics to said probing tip when saidprobing tip cartridge is in mating relationship with said main probinghead body.
 17. The system of claim 16, said electrical contact mechanismprotruding from said main probing head body.
 18. The system of claim 16,said electronics being selectively electrically coupled to a signaltesting instrument via a cable.
 19. The system of claim 16, said probingtip cartridge being held in place by at least one foot extending intosaid main probing head body.